Large quantities of fish are processed for canning and preservation in various ways, all requiring manual manipulation for the removal of entrails and waste material as well as the removal of fins, scales, skin and other waste matter. For many reasons well known to those engaged in the fish processing art, these operations have been conducted in the past primarily by hand labor. To reduce the cost and labor involved, various proposals have been made utilizing power equipment. Illustrative of these proposals are the teachings found in the U.S. Pat. Nos. 1,615,134 to Price; 2,565,727 to Henderson; 2,683,893 to Baader; 2,893,052 to Schlichting; 2,913,759 to Evich; 3,076,997 to Evich; and 3,561,044 to Evich.
In general, these various proposals have limited objectives and capabilities. For example, Price proposes a power-driven abrading roller for removing scales of a fish held in the operator's hands with the aid of tongs. Baader proposes a rotating loading table for transferring fish onto a second table operable to pass fish past slitting, trimming, and dressing devices primarily restricted to removing the opposite ends of a fish and its entrails. Schlichting is also concerned with the provision of a machine for passing fish past cutting knives each designed for performing a different operation. Evich U.S. Pat. No. 2,915,759 proposes two machines, one of which is designed to cut the throat of a fish conveyed past a rotating knife and the second performing a slitting operation lengthwise of the fish belly. Henderson discloses a fish dressing apparatus for passing predressed and quartered tuna past two independent processing stations each equipped with photoelectric controlled dressing knives, operable to remove dark meat characteristic of the tuna species. The apparatus requires manual inversion of the fish before processing by the second processing station.
The two latest Evich patents propose apparatus for advancing fish fillets past several groups of power-driven scale-removing dressing rollers. In the earlier U.S. Pat. No. 3,076,997 patent, the rollers are mounted transversely of the ends of arms restricted to pivotal movement in different radial planes extending lengthwise of the advancing fillets. These arms are equipped with sensor means controlling a pneumatic actuator for adjusting the dressing roller in a radial plane relative to the fillet. To avoid the wasteful and excess removal of flesh by this general arrangement, the last issued Evich patent proposes a more sophisticated servo adjusting mechanism for the dressing rollers. In this machine, the wide dressing rollers are mounted on arms arranged in an arc about the fillet conveyor and pivot in radial planes as well as about the axes of their respective supporting arms rather than about an axis tangent to the area of the rollers in dressing contact with the fillet as is crucially important to efficient and non-wasteful dressing. Each arm is provided with a complex pneumatic-hydraulic actuator operable to shift the arms in the radial planes in response to a fillet-engaging, rockable sensor embracing and pivoting about the axis the dressing rollers. The multiplicity of dressing rollers, each controlled by independently operable complex servo control systems of the type just mentioned involve difficult and costly maintenance and operating problems and has been found inadequate to avoid the removal of excess fillet flesh.